Blind stitch sewing machine



Oct. 11, 1938; R, KELSO 2,132,791

BLIND STITCH SEWING MACHINE Filed Jan. 4, 1936 6 Sheets-Sheet l Oct. 11, 1938. R. s. KELSO 2,132,791

BLIND STITCH SEWING MACHINE Filed Jan. 4, 1936 6 Sheets-Sheet 2 rlull. I

l l i 1' I I l I I l l I Oct. 11, 192,23.v

R. s. KELSO 2,132,791

BLIND STITCH SEWING MACHINE Filed Jan. 4, 1936' 6 Sheets-Sheet 5 Oct. 11, 1938. R. s. KELSO BLIND STITCH SEWING MACHINE Filed Jan. 4, 1936 6 Sheets-Sheet 4 Oct. 11, 1938.

R. S. KELSO BLIND STITCH SEWING MACHINE Filed Jan. 4, 1936. 6 Sheets-Sheet 5 1h n v m INI rlllllll Illllllll BLIND STITCH SEWING MACHINE Filed Jan. 4, 1936 6 Sheets-Sheet 6 Patented Oct. 11, 1938 i g UNITED STATES PATENT OFFICE BLIND STITCH SEWING MACHINE Ralph Simpson Kelso, St. Louis, Mo., assignor to Lewis Invisible Stitch Machine Company, St. Louis, Mo., a corporation of Maine Application January 4, 1936, Serial No. 57,613 22 Claims. (Cl. 112-176) This invention relates to new and useful imtween the main shaft and the 4-motion top feed, provements in blind stitch sewing machines genand between the main shaft and the looper, erally, although more particularly to blind stitch Figure 6 is a diagram showing the variable sewing machines employed in hemming operalooper speed travel, tions. Figure 7 is a detail view showing the driving 5 Ihe principal object of the invention is to connection between the main shaft and the oscilprovide a blind stitch sewing machine of the latory ridge carrying shaft, 1 double thread chain stitch type for seaming hems, Figure 8 is a detail elevation showing the reducby means of which a line of stitches will be formed tion gear coupling between the main shaft and 1G to unite the hem fold to the body fabric, the the pitrnan which oscillates the looper carrying 10 connecting portions of the needle thread between shaft, adjacent needle loops being positioned in a Figure 8a s an elevation of the driving diSe, straight line in parallelism with the inner edge of i ur 9 s a det l elevation o the p feed the hem and the enchained looper thread loops mechanism, the view showing particularly the being disposed under the inner edge of the hem means for imparting up and down movements to and thereby concealed from view. the feed dog,

Another important object of my invention lies F gu e 0 s a de l V w Showing the mechain the provision of a threaded non-avoiding reniSm for imparting the back and forth moveciprocatory looper which cooperates with a neem ts o e e d d zo rile mounted for reciprocation across therline of Figure 1 s a bottom p v of the feed, the looper having a path of travel in a Wardly extending m h w p r i l rly h single straight line in the line of feed and being D r f h o p r me n m, and t p located entirely on that side of the ridge forming feedmechanism, element opposite the point of needle penetration Figure 12 is a p P1311 View Of the Presser foot, 5in thefabric, whereby the feed of the fabric and Figure 13 is an enlarged v w w ng a h m the rearward stroke of the needle will effect the Seamed by my invention,

opening of the loo-per thread loop for entrance Figure 14 is an enlarged View of the Presser by the 1 4 foot, the needle, and the fabric being hemmed,

A f th object of the inventioh lies in the the view showing the looper at the rear end of its provision f means f reciprocating the looper stroke and the needle at the forward end of its 30 whereby the speed travel of the looper during the stroke last part of its forward. stroke will be increased Figure is Similar View but Showing the to thereby better insure the looper entering the looper movmg forwardly through the needle thread loop, d1 t nee e mead 100p and to decrease the speed Figure 16 1s a similar view but showing the travel of the looper during the first part of its backward stroke to thereby better insure the looper the forwar-d end of Its Stroke and the needle at the end of its backward stroke, and needle entering the looper thread triangle. Figure 17 is a Similar View but showing the With these and other objects in view which will looper being moved rearwardly and the needle more fully appearthe nature of the invention will in a position about to enter the looper thread it be more clearly understood by following the de- 10op the appended claims and the several Like reference numerals designate correspondvicws illustrated in the accompanying drawings. mg Darts throughout the several fi ur f the In the drawings: drawings Figure 1 is a p P View Of a Sewing My invention is adapted especially for joining 45 chine constructed in accordance with my invena h A t i body f b i or b layer B by a tion, line of blind stitches, as shown in Figure 13. The

Figure 2 is a left hand elevation thereof, the inner edge of the 'hem is indicated at a, and the bas being Omitted, hem may have an inturned edge portion a if Figure 3 is a perspective view of the looper supdesired. A needle thread C and a looper thread 60 porting bracket, D are employed to form a line of Grover and Figure 4 is a perspective view of the looper Baker stitches, which are otherwise known as guide, double-lock and double-chain stitches. The Figure 5 is a partial rear end elevation, partly stitches include needle thread loops 0 which are in section, showing the driving connections bespaced equidistantly apart and pass downwardly 55 ill) through the hem at points the connecting portions of the thread between the loops being arranged in a straight line and in parallelism to the inner edge a of the hem. Certain of these needle loops enter and emerge from the upper face of the body fabric as indicated at c to thereby form anchor stitches E which function to join the hem with the body fabric, while other needle loops miss the body fabric entirely to thereby form resultant skip stitches F. The

enchained loops d of the looper thread which are concatenated with the needle loops 0, are all located between the hem and the body fabric and are consequently concealed from view by the hem. It will be understood, anchor stitches, or alternate anchor and skip stitches, or any combination thereof, may be employed.

The machine of my invention includes a base 5 having a standard 6 projecting upwardly from the rear right hand corner thereof, an arm 7 which extends laterally from the upper end of said standard, and an arm 8 which extends forwardly from the left hand end of the arm 7. Fixed to the free end of the arm 8 in the usual manner is a horizontal presser foot 9 having a centrally located and longitudinally extending opening it? formed therein. Journaled in the laterally extending arm 7 is a main shaft H and journaled in the arm 8 is an oscillatory needle shaft i2 which is driven from the main shaft by a connection indicated generally at E3. The needle shaft i2 is disposed directly above the opening ill in the foot, and fixed to the outer end of the shaft is a needle arm l carrying a curved needle l5. Thus when the needle shaft i2 is oscillated the needle l5 will reciprocate transversely across the opening it in the presser foot. It will be noted at this time that the penetrating stroke of the needle l5, as viewed from the front of the machine, is from right to left.

Rigid with the base 5 is a post l6 which is located in a plane in advance of the standard 6 and pivotally supported on the upper end of this post is a work support i7 having a lateral extension l8 which projects under the presser foot 9, the work support I! being yieldably held against depression by a spring (not shown). The upward movement of the work support is adjustably limited by a stop l9 mounted on the work support ii and cooperating with the machine frame as shown in the Mueller Patent 2,018,186, Oct. 22, 1935.

As previously stated this machine is particularly intended for hemming operations and to this end means are provided for projecting a ridge of material upwardly through the presser foot opening lil into needle penetrating position during each cycle. A disc 2b is fixed to the end of a rock shaft 2i which is journaled in bearings on the under side of the work support H. The disc is provided with high and low peripheral portions 22 and 23 respectively, arranged in tandem, and this shaft 2i is oscillated for dilferent angular amounts by driving connections with the main shaft l l whereby the high and low portions of the disc will register successively with the needle during the penetrating strokes thereof. Thus at the rear end of one oscillation stroke the needle will engage both the hem A and the body fabric B to form a resultant anchor stitch E and at the rear end of the next stroke the needle will engage the hem A only to form a resultant skip stitch F. The driving connections between, the main shaft H and the disc shaft 2i however, that all are shown in Figures 7 and 8 and are as follows: Fixed to the main shaft I! is a driving eccentrio 24 and surrounding this eccentric is an eccentric sleeve 25 which is positively rotated on the eccentric but at one-half the speed thereof. A disc 26 is loosely mounted on the main shaft II and is provided with a radial slot 2? for receiving a slide block 28 fixed to the eccentric sleeve 25 by a shank 29. A driving gear 34 is fixed to the main shaft ii, and rotatable on a stationary shaft 32 mounted in the frame standard 6 is'a reduction gear unit including a large gear 33 and a small gear 35, the former being in constant mesh with the driving gear 34 and the latter being in constant mesh with a. gear 31 fixed to the disc 2%. This reduction gear coupling is similar to that shown in the Mueller Patent 1,989,602, of Jan. 29, 1935. The gear coupling ratio is such that the eccentric sleeve 25 is rotated once during every two revolutions of the main shaft l l. In order to rock the disc shaft 2| from the eccentric and eccentric sleeve 25, I have provided a link 36 having one end fitting around the eccentric sleeve 25 and the other end pivotally connected to a rock arm 37! which is clamped to the disc shaft 2 i Thus by these connections the high and low portions 22, 23 of the disc will successively register with the needle. A vertically yieldable work clamp 38 is mounted on the lateral extension 58 of the work support I! and cooperates with the lower face of the presser foo-t 9 in the usual manner to clamp the fabric against the thrust of the needle.

A top feeding mechanism for feeding the material rearwardly up to and past the needle includes a l-motion feed dog 39 having a front feed section 4i and a rearwardly spaced feed section ii, said sections being connected by a longitudinally extending bridge 42 forming a resultant opening at thereunder. This feed dog 39 is attached to a feed bar 4 1 by screws 45. The feed sections operate in the opening iii of the presser foot and against the upwardly spring pressed work clamp 38, the front section 43 being located in front of the needle path and the rear section 45 in rear of said path. The feed bar 45 is raised and lowered by a train of mechanism from the main shaft ll, and is moved back and forth by a train of mechanism operated from said main shaft. A bell crank lever 48 is pivoted at its angle as at 41 to the forwardly extending arm 8 of the frame. This bell crank lever includes a forwardly extending arm 38 and a downwardly extending arm 49. A link 56 is pivotally connected at its upper end as at 5! to the arm 48 and at its lower endas at 52 to the feed bar 44. The rear end of the feed bar is provided with an inclined open ended slot 53 which has sliding connection on a bearing pin 5% fixed to the forwardly extending frame arm 8. A pitman 55 is pivotally connected at its forward end as at 56 to the depending arm 49 of the bell crank lever 46 and the rear end of this pitman is connected with an eccentric 5T fixed on the main shaft II. It will thus be seen that upon rotation of the main shaft, the eccentric 51 will rock the bell crank lever 46 which, through the medium of the link 5|, will raise and lower the feed bar 44. In order to move the feed bar back and forth, I have provided a slotted segment 58 which is pivoted at its upper end as at 59 to the forwardly extending frame arm 8. A driving link 60 is pivotally connected at its forward end as at 6| to the feed bar 34 and the rear end of this link is adjustably connected to the slotted segment 58 by a clamping bolt 62, the slot. of the segment being arcuate and having for its center the pivot 9 I. The slotted segment 58 is pivotally connected as at 63 to a sleeve, 64 which surrounds an eccentric 65 fixed on the main shaft II. rotation of the main shaft II, the eccentric will impart swinging movements to the slotted segment 58 and this segment through themee dium of the link will impart back and forth movements to the feed bar 44. By adjusting the clamping bolt 62 lengthwise of the slotted seg ment 58 the length of feed travel imparted to the feed dog 39 may be readily varied.

Cooperating with the needle is a looper 68 which is threaded with the looper thread D. This looper is fixed to the forward end of a looper bar 87 extending longitudinally of the frame arm above the needle I5 but also above the presser foot 9 and its path of movement is in the line of feed or at right angles to the plane of needle reciprocations. In order to reciprocate the looper longitudinally from the main shaft I l, I have provided the looper bar 61 with a depending clamping arm 12, the upper end of the arm being formed into a split clamp 13 which surrounds the looper bar 81 and is clamped thereto by a screw 14. A pitman 15 has its forward end pivotally connected as at 16 to the lower end of the clamping arm 12 and its rear end engaged with an eccentric pin TI fixed to a sleeve 18 secured on the main shaft II. The looper bar 61 is retained against axial rotation by means of a guide shoe l9 which is preferably formed integral with the clamping arm 12 and cooperates with an up wardly extending guide plate. attached to the bracket 19 by screws 8|. It will be noted that the looper bar 51 is in the same horizontal plane as the main shaft I I and that the pivotal connec tion I9 is located below said plane. Consequently a variable speed travel is imparted to the looper during its backward and forward movements whereby the looper during the first part of its forward stroke will have a relatively fast speed travel while entering the needle thread loop, and

whereby the looper will have a relatively slow speed travel during the first part of the backward stroke thereof while the needle is entering the looper thread loop. In Figure 6, I have disclosed a diagram showing the variable looper travel.

The needle I5 is provided along its forward side with a shallow groove or spreader 82 which functions to drag the looper thread loop which is around the needle, toward the right and out of the line of feed and under the bridge 42 of the feed dog. Consequently the front feed portion 49 functions to feed the material up to the needle and the rear portion 4| of the feed dog functions to feed the material rearwardly away from the needle.

Thus. upon.

Anedge guide 83 is attached to the front end of the presser foot 9 and includes a vertical guide portion which projects downwardly into the presserv foot opening I0 and at the left side of the front feed section 40.

A spring plate 84 is mounted on the presser foot 9 at the forward end thereof and at the right hand side of the opening l9, and includes a laterally extending arm 85 which overhangs the disc 29. This arm 85 is disposed in front of the path of the needle I5 and under the bridge 42 of the feed dog, and the free end of said arm is formed with a forwardly extending recess 88 and a rearwardly extending finger 81. The slot 86 receives the edge a of the hem A, the arm 85 is pressed downwardly against the hem which is over the disc 28, and the finger 81 supports the edge a of the hem against the penetrating thrust of the needle I5.

The needle thread C is led forwardly through a tension 88 mounted on a bracket 89 attached to the rear end of the frame arm 8, thence through a thread guide 98 carried by a tension or control spring 9! mounted on an upstanding bracket 92 attached to the front end of the frame arm 8, and thence through a thread guide 93 formed in the top of the bracket 92. A forwardly extending bracket arm 9 t is attached by a screw 95 to the forward end of the frame arm 8, and carries a stationary thread guide 98 located above the path of needle travel and in alinement with the needle shaft I2. The needle thread passes from the guide 99, thence through the guide 93, thence through the guide 95, thence through a thread guide 91 attached to the lower end of the needle arm I4, and then to the needle eye.

Thus it will be seen that the location of the stationary needle thread guide 96 coupled with the control spring 9i and the associated thread guide the needle thread will be held taut and will remain in the long groove of the needle which is formed in the underside thereof as usual. Consequently the thread will not become abraded which would occur if the thread were caused to move intermittently in and out of said groove.

The looper thread D is led forwardly through a tension 98 mounted on the bracket 89, thence through a guide 99 mounted on the forward end of the bracket arm 94 and located in advance of the path of needle travel, thence downwardly and rearwardly to a. guide l 98 located on the forward end of the looper shaft 61 and adjacent the rear end of the looper 66, and thence to the looper eye iEiI.

Thus it will be noted that because of the posi tion of the thread guide 99, the looper thread will be inclined between said guide 99 and the thread guide I99 at the rear end of the looper;

that as the looper moves forwardly the looper thread feeds through the guide I09; that the length of the looper thread between these guides 99 and I99 becomes reduced in proportion to the amount of the forward travel of the looper; that the difference in the length of the thread between the guide 99 and I99 when the looper is at the forward end of its travel and when the looper is at the rear end of its stroke equals the amount of thread employed in forming the shortest stitch;

7 that when the length of the stitch is increased; a corresponding amount of thread is pulled from the supply during the last part of the forward movement of the looper; and that by reason of the location of the guide 99 the thread will remain in the groove of the looper during the back- Ward movement thereof.

It is. of course to be understood'that the details of structure and arrangement of parts may be variously changed and modified without departing from the spirit and scope of my invention.

I claim:

1. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, and a threaded looper mounted for reciprocations in a single straight line in the line of feed for cooperation with the needle, the looper passing above the needle in both strokes of each reciprocation.

2. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed and provided with a spreader groove, and a threaded looper mounted for reciprocations in a single straight line in the line of feed for cooperation with the needle, the needle-loop penetrating movement of the looper being in a direction opposite the direction of feed and the looper passing above the needle in both strokes of each reciprocation.

3. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, a threaded looper mounted for straight line reciprocations in the line of feed for cooperation with the needle, and means for reciprocating said looper including devices for imparting a relatively slow movement to the looper during the first part of the return travel thereof.

4. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, a threaded looper mounted for straight line reciprocations in the line of feed for cooperation with the needle, the needleloop penetrating movement of the looper being in a direction opposite the direction of feed, and means for reciprocating said looper including devices for imparting a relatively slow movement to the looper during the first part of the return travel thereof.

5. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, a threaded looper mounted for straight line reciprocations in the line of feed for cooperation with the needle, and means for reciprocating said looper including devices for imparting a relatively fast movement to the looper during the first part of the forward travel thereof.

6. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, a threaded looper mounted for straight line reciprocations in the line of feed for cooperation with the needle, and means for reciprocating said looper including devices for imparting a relatively fast movement to the looper during the first part of the forward travel thereof and a relatively slow movement to the looper during the first part of the return travel thereof.

'7. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, a threaded looper mounted for straight line reciprocations in the line of feed for cooperation with the needle,

the needle-loop penetrating movement of the looper being in a direction opposite the direction of feed, and means for reciprocating said looper including devices for imparting a relatively fast movement to the looper during the first part of the forward travel thereof and a relatively slow movement to the looper during the first part of the return travel thereof.

8. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, and a threaded looper mounted for reciprocations in the line of feed for cooperation with the needle and having its needle-loop penetrating movement in a direction opposite the direction of feed, said needle being provided with a transverse seat for receiving the looper thread loop during the return stroke of the needle to thereby move said loop laterally out of the path of the forwardly moving looper.

9. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, and a threaded looper mounted for straight line reciprocations in the line of feed for cooperation with the needle and having its needle-loop penetrating movement in a direction opposite the direction of feed, said needle being provided with a transverse seat for receiving the looper thread loop during the return stroke of the needle to thereby move said loop laterally out of the path of the forwardly moving looper.

10. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprocations across the line of feed, and a threaded looper mounted for reciprocations in the line of feed for cooperation with the needle and having its needle-loop penetrating movement in a direction opposite the direction of feed, said needle being provided with a transverse seat for receiving the looper thread loop during the return stroke of the needle to thereby'move said loop laterally out of the path of the forwardly moving looper, and means for reciprocating said looper including devices for imparting a relatively fast movement to the looper during the first part of the forward travel thereof.

11. In a sewing machine stitch forming mechanism, the combination with a feeding mechanism, of a threaded needle mounted for reciprooations across the line of feed, a ridge forming element for presenting a ridge of material to the needle, a threaded looper cooperating with the needle and mounted for horizontal straight line reciprocations in the line of feed and on that side of the ridge forming element opposite the point of needle penetration, the needle-loop penetrating movement of the looper being in a direction opposite the direction of feed, said needle being provided with a transverse seat for receiving the looper thread loop during the return stroke of the needle to thereby move said loop laterally out of the path of the forwardly moving looper.

12. In a sewing machine, the combination with a frame including a forwardly extending arm, of a horizontal presser foot fixed to the front end of said arm and having an opening, a main shaft journaled in the rear end of said arm, a needle shaft extending longitudinally of and journaled in said arm, a needle mounted on said needle shaft for reciprocations above the foot and across the opening therein, driving connec- "tions between the main shaft and the needle shaft, a looper bar mounted on the frame arm between the main shaft and the needle for horizontal straight line movements longitudinally of the arm, means for retaining'the looper bar against 'axial rotation, a threaded looper fixed td'the forward end of the bar for cooperation with theneedle, and driving connections between the main shaft and the looper bar. ll)

13. In a sewing machine, the combination with a frame including a forwardly extending arm,

-of;'a horizontal presser foot fixed to the front i nee'dle" shaft for reciprocatiohs above and across theopening therein, driving connecend of said arm and having an opening, a main shaft journaled in the rear end of said arm, a

needle shaft extending longitudinally of and 4 journaled in' said arm, a needle mounted on said the foot tions between the main shaft and the needle shaft, a looper bar mounted on the frame arm between the main shaft and the needle for horizontal straight line movements longitudinally of the arm and in substantially the same horizontal plane as the main shaft, means for retaining the looper bar against axial rotation, a threaded looper fixed to the forward end of the bar for cooperation with the needle, and driving connections between the main shaft and the looper bar comprising a downwardly extending arm fixed to the looper bar, a driving eccentric fixed to the main shaft, and a pitman connected at one end to the eccentric and at its other end to the downwardly exending arm at a point below the looper bar.

14. In a sewing machine, the combination with a frame including a forwardly extending arm, of a horizontal presser foot fixed to the front end of said arm and having an opening, a main shaft journaled in the rear end of said arm, a needle shaft extending longitudinally of and journaled in said arm, a needle mounted on said needle shaft for reciprocations above the foot and across the opening therein, driving connections between the main shaft and the needle shaft, a looper bar mounted on the frame arm between the main shaft and the needle for horizontal straight linemovements longitudinally of the arm, means for retaining the'looper bar against axial rotation, a threaded looper fixed to the forward end of the bar for cooperation with the needle, driving connections between the main shaft and the looper bar, and a imotion top feed mechanism for feeding the fabric up to and past the needle comprising a feed dog having spaced sections respectively disposed in front of and in rear of the needle path of travel and at one side of the looper travel, a

7 feed bar extending longitudinally of the work arm, connections between the main shaft and the feed bar for imparting up and down movements to the feed bar, and other connections between the main shaft and the feed bar for imparting back and forth movements to said feed bar.

- 15. In a looper thread control for sewing machines, the combination with a stitching head, of a stationary presser foot mounted on said head and provided with a longitudinal opening, a threaded needle mounted on said head for reciprocations above the foot and across the opening thereof, a threaded looper mounted on said head for cooperation with said needle and having its needle-loop entering and shedding movements across the path of needle movement, a tension for the looper thread mounted on the ed on said head between the tension and the looper and located in front of the needle and in substantial 'alinement with the looper.

16. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening,- of a feeding mechanism, means for projecting a ridge of material upwardly through the opening into needle penetrating position, and a stitch forming mechanism operating entirely above the footincluding a threaded needle having reciprocatory movements across said opening and in a plane transverse to ;the'1ine of feed, and a cooperating threaded looper having reciprocatory movements in a single straight line in the line of feed,

1'7. In a blind stitch sewing machine, the combination with a-stationary presser foot having an opening, of a feeding mechanism, means for projecting a ridge "of material upwardly through the opening into needle penetrating position, and a stitch forming mechanism operating entirely above the foot including a threaded needle having reciprocatory movements across said opening and in a plane transverse to the line of feed, and a cooperating threaded looper having reciprocatory movements in a single straight line in the line of feed, the needle penetrating movement of the looper being in a direction opposite the direction of feed.

18. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding mechanism, means for projecting a ridge of material upwardly through the opening into needle penetrating position, and a stitch forming mechanism operating entirely above the foot including a threaded needle having reciprocatory movements across said opening and in a plane transverse tothe line of feed, a cooperating threaded looper having reciprocatory movements in a single straight line in the line of feed, and means for reciprocating said looper including devices for imparting a relatively slow movement to the looper during the first part of the return travel thereof.

19. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding mechanism, means for projecting a ridge of material upwardly through the opening into needle penetrating position, and a stitch'forming mechanism operating entirely above the foot including a threaded needle having reciprocatory movements across said opening and in a plane transverse to the line of feed, a cooperating threaded looper having reciprocatory movements in a single straight line in the line of feed, the needle penetrating movement of the looper being in a direction opposite the direction of feed, and means for reciprocating said looper including devices for imparting a relatively slow movement tothe looper during the first part of the return travel thereof.

20. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding mechanism, means for projecting a ridge of material upwardly through the opening into needle penetrating position, and a stitch forming mechanism operating entirely above the foot including a threaded needle having reciprocatory movements across said opening and in a plane transverse to the line of feed, and a cooperating threaded looper having reciprocatory movements in a single straight line in the line of feed, said needle being provided with a transverse seat for receiving the looper thread loop during the return stroke of the needle to thereby move said loop laterally out of the path of the forwardly moving looper.

21. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding mechanism, means for projecting a ridge of material upwardly through the opening into needle penetrating position, and a stitch forming mechanism operating entirely above the foot including .a threaded needle having reciprocatory movements across said opening and in a plane transverse to the line of feed, and a cooperating threaded looper having reciprocatory movements in a single straight line in the line of feed, the needle penetrating move ment of the looper being in a direction opposite the direction of feed, said needle being provided with a transverse seat for receiving the looper thread loop during the return stroke of the needle to thereby move said loop laterally out of the path of the forwardly moving looper,

22. In a blind stitch sewing machine, the combination with a stationary presser foot having an opening, of a feeding mechanism, means for projecting a ridge of material upwardly through the opening into needle penetrating position, and a stitch forming mechanism operating entirely above the foot including a threaded needle having reciprocatory movements across said opening and in a plane transverse to the line of feed, a cooperating threaded looper having reciprocatory movements in a single straight line in the line of feed, and means for reciprocating said looper including devices for imparting a relatively slow movement to the looper during the first part of the return travel thereof, said needle being provided with a transverse seat for receiving the loo-per thread loop during the return stroke of the needle to thereby move said loop laterally out of the path of the forwardly moving looper.

RALPH SIIVLPSON KELSO. 

